How many followers do you have? The rise of social media has brought with it a new kind of celebrity, the digital influencer. These megastars of Instagram and YouTube have upended the advertising industry by converting their virtual followers into real-world currency. Big-name brands have flocked to online stars, paying them millions to endorse their products, but the market has been criticised as being a 'Wild West' of misleading and unregulated advertising, plugging everything from bogus diet drinks to online gambling to young audiences. Panorama reporter Catrin Nye investigates whether companies are being up front and the impact this new form of advertising is having on consumers.